An apparatus for controlling operating characteristic quantities of an internal combustion engine is known from German published patent application DE-OS No. 2,847,021 and British patent application No. 2,034,930 which is a Convention application based on the German application. These applications disclose an arrangement for controlling operating characteristic quantities of an internal combustion engine to optimal values, especially operating characteristic quantities such as power or the specific fuel consumption. This arrangement includes a control arrangement which pre-controls the engine variables and which varies the engine variables at selectable times or at the occurrence of definite operating conditions. The pre-control values are influenced by a control of the internal combustion engine to optimum power or to minimal specific fuel consumption. An extreme-value control is also known as an optimizer and is suggested for a control method to change the pre-control values.
Although this control arrangement has performed well, improvements can be made thereto with respect to various facets thereof. Especially the influence of various factors from outside such as air temperature or elevation which act on all characteristic field values of the pre-control characteristic field in the same manner for systems wherein air mass is not measured are not optimally considered by the above-mentioned known arrangement.